A student measures the uptake of substance X by cells. The concentration of X is kept higher outside the cells than inside. A treatment stops energy being supplied from respiration without changing membrane permeability or the concentration gradient.
Uptake continues, but at a lower rate.
Which explanation is best supported?
all uptake was by diffusion, and the treatment stopped diffusion completely
all uptake was by active transport, and the treatment increased active transport
uptake included osmosis and active transport, and only osmosis stopped
uptake included diffusion and active transport, and only active transport stopped
41 exam-style questions on Edexcel GCSE Biology 1.4 Transport across cell membranes, covering 1.4.1 Transport into and out of cells and 1.4.2 Percentage gain and loss in osmosis. Each one has a worked solution and a mark scheme showing where the marks go.